PPT: Electric Current and Its effects | Science Class 7 (Old NCERT) PDF Download

 Page 1


Electric Current & 
its Effects
Page 2


Electric Current & 
its Effects
Introduction
Life Without 
Electricity
Imagine a world with no lights, 
no gadgets, and no 
communication systems. Our 
modern conveniences would 
cease to exist without the 
power of electricity.
The Invisible Force
Ever wondered how flipping a 
switch lights up a room? In 
this chapter, we'll explore how 
electric current works and 
powers our everyday lives.
Electric Components
These are the parts of an electric circuit that help it function, like 
batteries, switches, and bulbs or motors. Each component has a 
specific role in making the circuit work properly.
Page 3


Electric Current & 
its Effects
Introduction
Life Without 
Electricity
Imagine a world with no lights, 
no gadgets, and no 
communication systems. Our 
modern conveniences would 
cease to exist without the 
power of electricity.
The Invisible Force
Ever wondered how flipping a 
switch lights up a room? In 
this chapter, we'll explore how 
electric current works and 
powers our everyday lives.
Electric Components
These are the parts of an electric circuit that help it function, like 
batteries, switches, and bulbs or motors. Each component has a 
specific role in making the circuit work properly.
Symbols of Electrical Components
Electric Cell & Battery
An electric cell is represented by a longer 
line (positive terminal) and a shorter, 
thicker line (negative terminal). A battery 
is a combination of multiple cells, shown 
by repeating the cell symbol.
Switch
Switches are represented by different 
symbols indicating whether the circuit is 
ON or OFF. They control the flow of 
electricity through the circuit.
Bulb & Wire
Bulbs and wires also have standardized 
symbols for easy representation in 
circuit diagrams, making complex circuits 
easier to understand and draw.
Page 4


Electric Current & 
its Effects
Introduction
Life Without 
Electricity
Imagine a world with no lights, 
no gadgets, and no 
communication systems. Our 
modern conveniences would 
cease to exist without the 
power of electricity.
The Invisible Force
Ever wondered how flipping a 
switch lights up a room? In 
this chapter, we'll explore how 
electric current works and 
powers our everyday lives.
Electric Components
These are the parts of an electric circuit that help it function, like 
batteries, switches, and bulbs or motors. Each component has a 
specific role in making the circuit work properly.
Symbols of Electrical Components
Electric Cell & Battery
An electric cell is represented by a longer 
line (positive terminal) and a shorter, 
thicker line (negative terminal). A battery 
is a combination of multiple cells, shown 
by repeating the cell symbol.
Switch
Switches are represented by different 
symbols indicating whether the circuit is 
ON or OFF. They control the flow of 
electricity through the circuit.
Bulb & Wire
Bulbs and wires also have standardized 
symbols for easy representation in 
circuit diagrams, making complex circuits 
easier to understand and draw.
Electrical Circuit & Diagram
What is an 
Electrical 
Circuit?
An electrical circuit is 
a closed path formed 
by the interconnection 
of electrical 
components through 
which electric current 
flows. This path allows 
electricity to travel 
from the power source 
through the 
components and back.
Power 
Requirements
When a device like a 
bulb requires more 
power than a single 
cell can provide, it 
needs to be 
connected to a 
battery instead. A 
battery supplies the 
necessary power for 
such devices by 
combining two or 
more cells.
Batteries in Daily 
Life
Batteries are used in 
many devices, such as 
torch lights, mobile 
phones, calculators, 
and even automobiles. 
They are formed by 
connecting the 
positive terminal of 
one cell to the 
negative terminal of 
another.
Page 5


Electric Current & 
its Effects
Introduction
Life Without 
Electricity
Imagine a world with no lights, 
no gadgets, and no 
communication systems. Our 
modern conveniences would 
cease to exist without the 
power of electricity.
The Invisible Force
Ever wondered how flipping a 
switch lights up a room? In 
this chapter, we'll explore how 
electric current works and 
powers our everyday lives.
Electric Components
These are the parts of an electric circuit that help it function, like 
batteries, switches, and bulbs or motors. Each component has a 
specific role in making the circuit work properly.
Symbols of Electrical Components
Electric Cell & Battery
An electric cell is represented by a longer 
line (positive terminal) and a shorter, 
thicker line (negative terminal). A battery 
is a combination of multiple cells, shown 
by repeating the cell symbol.
Switch
Switches are represented by different 
symbols indicating whether the circuit is 
ON or OFF. They control the flow of 
electricity through the circuit.
Bulb & Wire
Bulbs and wires also have standardized 
symbols for easy representation in 
circuit diagrams, making complex circuits 
easier to understand and draw.
Electrical Circuit & Diagram
What is an 
Electrical 
Circuit?
An electrical circuit is 
a closed path formed 
by the interconnection 
of electrical 
components through 
which electric current 
flows. This path allows 
electricity to travel 
from the power source 
through the 
components and back.
Power 
Requirements
When a device like a 
bulb requires more 
power than a single 
cell can provide, it 
needs to be 
connected to a 
battery instead. A 
battery supplies the 
necessary power for 
such devices by 
combining two or 
more cells.
Batteries in Daily 
Life
Batteries are used in 
many devices, such as 
torch lights, mobile 
phones, calculators, 
and even automobiles. 
They are formed by 
connecting the 
positive terminal of 
one cell to the 
negative terminal of 
another.
Electric Circuit Diagrams
1
Circuit Representation
An electric circuit can be represented on paper using standardized symbols for each 
component. This representation is known as an Electric Circuit Diagram. The diagram 
includes a key or switch that controls the flow of electricity.
2
Open Circuit
When the key is switched off or in the open position, the circuit is incomplete, and 
electricity cannot flow, making it an open circuit. In this state, connected devices will not 
function.
3
Closed Circuit
When the key is switched on or in the closed position, the circuit is complete, allowing 
electricity to flow, making it a closed circuit. This enables connected devices to operate 
normally.
4
The Light Bulb Filament
Inside a light bulb, there is a thin wire called a filament. When electricity flows through 
the filament, it heats up and produces light. If the filament breaks, the circuit becomes 
incomplete, causing the bulb to stop glowing.